linux-kernel - [PATCH] cpufreq/amd-pstate: Remove unnecessary driver_lock in set

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Message-ID: <20250130085251.155146-1-dhananjay.ugwekar@amd.com>
Date: Thu, 30 Jan 2025 08:52:52 +0000
From: Dhananjay Ugwekar <dhananjay.ugwekar@....com>
To: <gautham.shenoy@....com>, <mario.limonciello@....com>,
	<rafael@...nel.org>, <viresh.kumar@...aro.org>
CC: <linux-kernel@...r.kernel.org>, <linux-pm@...r.kernel.org>, "Dhananjay
 Ugwekar" <dhananjay.ugwekar@....com>
Subject: [PATCH] cpufreq/amd-pstate: Remove unnecessary driver_lock in set_boost

set_boost is a per-policy function call, hence a driver wide lock is
unnecessary. Also this mutex_acquire can collide with the mutex_acquire
from the mode-switch path in status_store(), which can lead to a
deadlock. So, remove it.

Signed-off-by: Dhananjay Ugwekar <dhananjay.ugwekar@....com>
---
PS: This patch should ideally go before [1], as that patch uncovers this 
bug and actually leads to a deadlock when switching the amd_pstate driver 
mode.
[1] https://lore.kernel.org/linux-pm/e16c06d4b8ffdb20e802ffe648f14dc515e60426.1737707712.git.viresh.kumar@linaro.org/
---
 drivers/cpufreq/amd-pstate.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index d5be51bf8692..93788bce7e6a 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -740,7 +740,6 @@ static int amd_pstate_set_boost(struct cpufreq_policy *policy, int state)
 		pr_err("Boost mode is not supported by this processor or SBIOS\n");
 		return -EOPNOTSUPP;
 	}
-	guard(mutex)(&amd_pstate_driver_lock);
 
 	ret = amd_pstate_cpu_boost_update(policy, state);
 	refresh_frequency_limits(policy);
-- 
2.34.1